From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BD6EF606A31A for ; Thu, 29 Oct 2026 20:40:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kSJM4jh0 Received: by kanga.kvack.org (Postfix) id 88EF96B05DD; Thu, 29 Oct 2026 16:40:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8666B6B05DE; Thu, 29 Oct 2026 16:40:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 77CA26B05DF; Thu, 29 Oct 2026 16:40:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 4FEE96B05DD for ; Thu, 29 Oct 2026 16:40:41 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id D6BE94050D for ; Thu, 29 Oct 2026 20:40:40 +0000 (UTC) X-FDA: 85376832240.08.EB934D3 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf01.hostedemail.com (Postfix) with ESMTP id 1116C40007 for ; Thu, 29 Oct 2026 20:40:38 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=kSJM4jh0; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793306439; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=QSDRgnr69YPTIztges5CfT2KnEGoLvf21RQ7Ru6EwMk=; b=3CBjBt7paVOqiAPzYrtem222Why87N9U8WlriRUkmwt0iDLw8cqS8y8PnjOfXQq34GI02i M3zg9LRE/X8tpOL7OAlCeJxBvjA/HbQIn+FJJLHexyJeIcF9Lj68do2ruZu5sEvgU8Y3Z8 8a+KnaWxyB1BWWOhpfhhL86Sy21FawE= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=kSJM4jh0; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793306439; b=aq0OH4x6kNIgK/9PE6qukaYGi5hxZ/kHdBGmnF2yX/d3d7Mde0xNdb23wHkWi698+B3IQS I2IaC8wvc+giP2JCnjHl8a2pOPKv2ymFJ354b8jBTxwvdzWO5PP81h40Ea03MK+ofkiDeP zF8xM/zcQsGCC06lozdTcaNLNUfizAw= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 61A2C40803; Thu, 29 Oct 2026 20:40:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F16E01F01826; Thu, 29 Oct 2026 20:40:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793306438; bh=QSDRgnr69YPTIztges5CfT2KnEGoLvf21RQ7Ru6EwMk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=kSJM4jh0HrN4VoBlBOqhsPGwGw2Ay3L6UkwB26SEadkf6ghUVo2z8TB8QCJ9muHku 5O77SDUckn2sO3yoVq/4XT6gpdq26chxpQr5jmd+TFr7yyyjMEAT7vJlAlHNi2G586 9dRzcbSiqzIJZhkYCZd0MkRZjlSqG4A/IqkIfPVXCSD+uJYrJlLddKokdFu1Lpj4s+ AM4Rg32kxI2Hn7JiuuOIn7WunGYp4G6VoTkDjcU1gizGyXkzJyZ9GEOxzwegUo/KUo f8ea/Z5QTtcFqqdC8XZvDhfq5KUMWVmWRyPkk5jZK+YupM1MEDamRB8Ea2ZIKljyXO MS5d+tWdUKOVw== From: "David Hildenbrand (Arm)" Date: Thu, 29 Oct 2026 21:33:24 +0100 Subject: [PATCH v2 29/47] mm/mmu_notifier: set ->mm only after mmgrab() X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261029-fixes_core-v2-29-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> In-Reply-To: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Chris Mason , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2087; i=david@kernel.org; h=from:subject:message-id; bh=c82hKzDD/9RIfU3f00HaLlK2GVigMUUm/EjoMU8UlA8=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer+3QEZsaWVS8/Mt/6UkCdn1zjjE9rGt3nrrZJ0dxZ 1tMXZtlRykLgxgHg6yYIktQ8H2Dly/X1Va78THDzGFlAhnCwMUpABOJ9WX4H/prQtCmW1M9M2oK 9NuZ999n01ZTbl/OzdHgtG6HjKPSZ0aGF04lWz43hK3uUjCvqbrEzXLhdlBiS+zbzR6tTzNsL7N zAgA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 1116C40007 X-Stat-Signature: wkqbpm3bkbd3a7kpf635x3smm3qeamqt X-Rspam-User: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1793306438-289325 X-HE-Meta: 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 dUReiEgW G3y9/89lgtd+HZ0mn2ZYSEX/+BBn06nLW2u1h5WpZV4iU9frqk2+TxH//tPbuT/Jdx+aYpS6ZoUxNQXoHq8zAx58Pk+EuzH9Q8MJNmbL7SlzyLZutRtuYcCYtoRmyPl5mSRbXN1iBwdBK4WgKiFeW0qRQwYMENG2cLP8UtCoyelsWw/VW18q9ZcGf72e05GJmiVHVa+teK6FzG609O5kaWs432HfBY+K9Z5COLjuEdEWy9KaVoUxtgxoXu/VnjTYWYKPTPt8JgYmQbAWdu4G/Nz9LgFbc9D8xPLwBQkal8XEwXki6YpAckDsHn/OK+r2A82lHoJC+C1wZxTxR7MPMW64z00BZpyGl1DemC759nP0BHPEWaJQ3k935/tgVosNXuVFxIbJoUaGrH0VsLY1De/XjHo+Cy7SAROqaXmfddk6/L4I= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 From: Chris Mason Radeon uses a non-NULL notifier->mm to decide whether to call mmu_interval_notifier_remove() when freeing a buffer object. __mmu_interval_notifier_insert() sets ->mm before validating the range, so a wrapping userptr range can leave ->mm set after insertion fails. Cleanup then tries to remove an unregistered notifier for which no mm reference was acquired. Set ->mm only after mmgrab(), once insertion can no longer fail. While we could fix radeon's code instead, setting ->mm on success only makes the code more robust. Fix generated by an LLM and sent by Chris Mason in private. Fixes: 3506ff69c3ec ("drm/radeon: use mmu_interval_notifier_insert") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Reviewed-by: Gregory Price (Meta) Tested-by: Gregory Price (Meta) Reviewed-by: Lorenzo Stoakes (ARM) Signed-off-by: David Hildenbrand (Arm) --- mm/mmu_notifier.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 2e20f88e162d..a7bae5de5fed 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -947,7 +947,6 @@ static int __mmu_interval_notifier_insert( struct mmu_notifier_subscriptions *subscriptions, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops) { - interval_sub->mm = mm; interval_sub->ops = ops; RB_CLEAR_NODE(&interval_sub->interval_tree.rb); interval_sub->interval_tree.start = start; @@ -964,8 +963,12 @@ static int __mmu_interval_notifier_insert( if (WARN_ON(atomic_read(&mm->mm_users) <= 0)) return -EINVAL; - /* pairs with mmdrop in mmu_interval_notifier_remove() */ + /* + * Pairs with mmdrop in mmu_interval_notifier_remove(). Drivers take a + * non-NULL ->mm for "registered", so set it only with the reference. + */ mmgrab(mm); + interval_sub->mm = mm; /* * If some invalidate_range_start/end region is going on in parallel -- 2.43.0